LCA System Boundaries: Cradle-to-Grave vs. Cradle-to-Gate

Selective Laser Sintering is a powder bed fusion additive manufacturing process. It utilizes a high-power laser to selectively sinter, or fuse, particles of a polymer powder. A roller spreads a thin layer of powder over a build area, the laser scans a cross-section of the part, and the build platform lowers. This process repeats, building the object layer-by-layer.

ISO 9001 is the world's most recognized standard for Quality Management Systems (QMS). It provides a framework and a set of principles that ensure a common-sense approach to the management of an organization to consistently satisfy customers and other stakeholders. It is based on seven quality management principles, including a strong customer focus and a process-based approach.

B2B business models are often categorized as either vertical or horizontal. A vertical B2B model focuses on a single industry or 'vertical,' providing specialized products and services tailored to that sector's unique needs (e.g., software for dentists). In contrast, a horizontal B2B model offers a product or service that is applicable across multiple industries (e.g., accounting software or office supplies).

Design for Disassembly (DfD) is a design strategy focused on enabling the easy and cost-effective separation of a product's components and materials at its end-of-life. By prioritizing non-destructive separation, DfD facilitates repair, reuse, remanufacturing, and high-purity recycling. Key techniques include using mechanical fasteners over adhesives, modular construction, and clear material labeling to maximize value recovery.

The International Ergonomics Association divides the discipline into three primary domains of specialization: physical ergonomics focuses on human anatomical, anthropometric, physiological, and biomechanical characteristics as they relate to physical activity, cognitive ergonomics concerns mental processes like perception, memory, and reasoning, and finally organizational ergonomics deals with the optimization of sociotechnical systems, including organizational structures, policies, and processes.

The 1.5 sigma shift is an empirical correction used in Six Sigma calculations to account for the long-term dynamic variation of a process. It posits that over time, a process mean will tend to drift by about 1.5 standard deviations from its short-term centered position. This shift is the reason a 6 sigma process corresponds to 3.4 DPMO, not the theoretical 2 defects per billion.

The Juran Trilogy, developed by Dr. Joseph M. Juran, is a foundational quality management approach consisting of three interconnected processes: Quality Planning, Quality Control, and Quality Improvement. This framework provides a structured way for organizations to manage for quality. It emphasizes that quality does not happen by accident; it must be planned and managed systematically.

Parametric modeling is a CAD paradigm where designs are defined by parameters and constraints rather than just geometric shapes. Dimensions and relationships between features (e.g., parallelism, tangency) are stored as parameters. Modifying a parameter value automatically updates the entire model, maintaining the defined constraints. This approach facilitates design iteration, automation, and the creation of design families.

Fused Deposition Modeling (FDM), sometimes named Fused Filament Fabrication (FFF), a material extrusion technique, builds objects by selectively depositing molten material in a pre-determined path layer-by-layer. A thermoplastic filament is unwound from a coil and fed through a heated extruder nozzle. The nozzle melts the filament and deposits it onto a build platform, where it cools and solidifies, fusing with the layer below.

Life-Cycle Assessment (LCA) is a systematic methodology for evaluating the environmental impacts associated with all stages of a product's life. This "cradle-to-grave" or "cradle-to-cradle" analysis considers raw material extraction, processing, manufacturing, distribution, use, repair, maintenance, and final disposal or recycling. It quantifies inputs like energy and raw materials and outputs like emissions to air, water, and soil.

Solid-state batteries replace the liquid or polymer gel electrolyte of conventional batteries with a solid, ion-conducting material, such as a ceramic or solid polymer. This design aims to improve safety by eliminating flammable liquid electrolytes and to increase energy density and lifespan by enabling the use of high-capacity anodes, particularly pure lithium metal.

Six Sigma is a quality management methodology aiming for near-perfection. A process operating at a "six sigma" level has a yield of 99.9997%, meaning it produces only 3.4 Defects Per Million Opportunities (DPMO). This standard corresponds to a process where the nearest specification limit is six standard deviations away from the process mean, accounting for a 1.5 sigma shift in the mean over time (refer to the specific details on the debated 1.5 sigma shift as an empirical observation).

Rapid prototyping is a group of techniques used to quickly fabricate a scale model of a physical part or assembly using three-dimensional computer-aided design (CAD) data. In iterative design, it allows for fast creation of tangible models for user testing and stakeholder feedback, enabling quick design refinements before committing to expensive tooling and manufacturing processes.